Quartz crystals have been discovered swirling in the atmosphere of exoplanet WASP-17b

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Astronomers using the James Webb Space Telescope have discovered for the first time tiny quartz crystals containing silica – a common mineral on Earth – inside the atmosphere of a hot, burning exoplanet.

Silica nanoparticles, which appear on Earth in beach sand and are used to produce glass, are likely swirling from the clouds of the exoplanet, known as WASP-17b, according to the researchers.

First discovered in 2009, WASP-17b is a gas giant planet located 1,300 light-years from Earth. It is more than seven times the size of Jupiter, making it one of the largest exoplanets known to astronomers.

Researchers have detected quartz nanoparticles in high-altitude clouds using the Webb mid-infrared instrument, according to new research published Monday in the journal Webb. Astrophysical Journal Letters.

“We were thrilled,” David Grant, the study’s lead author and a researcher at the University of Bristol, said in a statement. “We knew from Hubble observations that there must be aerosols — small particles that form clouds or fog — in WASP-17 b’s atmosphere, but we didn’t expect them to be made of quartz.”

Minerals rich in silicon and oxygen, called silicates, are abundant on Earth, the Moon, and other rocky bodies in the solar system. Silicates are also incredibly common in the Milky Way. But until now, silicate grains detected in exoplanetary atmospheres have been based on magnesium, not quartz, which is made of pure silica.

“We were fully expecting to see magnesium silicate,” study co-author Hannah Wakeford, a senior lecturer in astrophysics at the University of Bristol, said in a statement.
“But what we see instead are likely the building blocks of those particles, the tiny ‘seed’ particles needed to form the larger silicate grains we detect in cold exoplanets and brown dwarfs.”

This discovery could enable researchers to understand the materials used to form planetary environments that are very different from what we know on Earth.

Wasp-17b takes 3.7 Earth days to complete one orbit around its star. Astronomers focused their observations on the exoplanet as it crossed in front of its star and starlight filtered through its atmosphere.

After 10 hours of observation, the team detected a sign indicating the presence of quartz nanoparticles.

The quartz crystals are likely hexagonal, like the larger geodes we know on Earth, but each one is only a millionth of a centimeter in size, so small that 10,000 grains could fit side by side across a human hair, according to the research. . Particles originate in the atmosphere.

“WASP-17 b is extremely hot — about 2,700 degrees Fahrenheit (1,500 degrees Celsius) — and the pressure where quartz crystals form high in the atmosphere is only about one-thousandth of what we experience on Earth’s surface,” Grant said. “Under these conditions, solid crystals can form directly from the gas, without going through a liquid phase first.”

The planet is tidally locked to its star, meaning one side always faces the star and experiences extreme temperatures, while the permanent “night” side of the planet is cooler. While the clouds could drift around the planet, they would likely evaporate on the hot dayside, which could cause the quartz particles to spin.

“The wind can move these tiny glass particles at thousands of miles per hour,” Grant said.

Webb’s sensitive discoveries allow researchers to gain a better understanding of the atmospheres, environmental conditions and weather on planets outside our solar system.

Hot gas giants, also called hot Jupiters, like WASP-17b are composed largely of hydrogen and helium, along with some water vapor and carbon dioxide. The discovery of silica in the planet’s atmosphere helps scientists get a broader idea of ​​the composition of WASP-17b.

“If we only consider the oxygen in these gases, and neglect to include all the oxygen trapped in minerals like quartz, we will dramatically underestimate their total abundance,” Wakeford said. “These beautiful silica crystals tell us about the inventory of different materials and how they all come together to shape the environment of this planet.”